New polymorph of CaHPO4 (monetite): synthesis and crystal structure

Аннотация

A novel form of anhydrous dicalcium phosphate CaHPO₄ (monetite) is synthesized hydrothermally and characterized by single crystal X-ray diffraction. It crystallizes in the orthorhombic space group Ccm2₁ with a = 6.242(1) Å, b = 6.994(2) Å, c = 7.003(3) Å, V = 305.73(16) ų and it has four independent unit formulas in the unit cell (Z = 4). A three-dimensional crystal structure can be described by {HPO₄}_n infinite zigzag chains linked by Ca–O bonds. The comparison to the crystal structures of other polymorphs is given.